[en] With approximately 90 living species, whales, dolphins and porpoises represent the most diverse clade of extant marine tetrapods. This high level of taxonomic diversity has been often related to ocean restructuring that resulted in an explosive radiation of oceanic dolphins within the past 10 Ma. However, this hypothesis does not entirely explain how organisms have faced environmental constraints suggesting other factors could also explain this burst of diversification. In marine taxa such as sharks and ichthyosaurs, morphological variations have been linked to several life-styles which have sustained their diversification in different adaptive zones. The aim of our study is to establish the relationship between the morphology of the axial skeleton of cetaceans, their ecology and their diversification. By combining the most extensive morphological dataset describing the axial skeleton of 73 cetacean species with cutting-edge phylogenetic comparative methods, we demonstrate that extant cetaceans have followed two distinct evolutionary pathways in relation to their ecology. Most oceanic species evolved towards an increased body size leading to gigantism in baleen whales. Interestingly, dolphins have evolved another way. While riverine and coastal species exhibit a small body size, lengthened vertebrae and a low vertebral count, small oceanic dolphins show an extremely high number of short vertebrae. We discuss how these modifications have operated as key innovations that contributed to the explosive radiation of dolphins.
Research Center/Unit :
FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
Disciplines :
Zoology
Author, co-author :
Gillet, Amandine ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Morphologie fonctionnelle et évolutive
Frederich, Bruno ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Morphologie fonctionnelle et évolutive
Parmentier, Eric ; Université de Liège - ULiège > Département de Biologie, Ecologie et Evolution > Morphologie fonctionnelle et évolutive
Language :
English
Title :
Evolution of cetacean backbone in light of phylogenetic and ecological constraints
Publication date :
22 July 2019
Event name :
12th International Congress of Vertebrate Morphology
Event organizer :
International Society of Vertebrate Morphologists
Event place :
Prague, Czechia
Event date :
from 21-07-2019 to 25-07-2019
By request :
Yes
Audience :
International
Peer reviewed :
Editorial reviewed
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]